It is well documented that one primary channel of infectious pathogen transfer from one person to another is the latter's touching an infected one or contacting a contaminated object, then touching his or her face with the now contaminated hand. Pathogens lying around the nose, eyes or mouth can be easily absorbed. The phenomenon is particularly common in connection with cold and flu viruses.
By the very nature of such interactions, it is virtually impossible to prevent contamination of the hands. The simple act of handling money, using restaurant flatware, or touching a door handle may result in the gathering of infectious pathogens.
Absorption of these pathogens through the eyes, nose or mouth can be limited by the wearing of goggles and face masks. However, those precautionary implements are cumbersome, can be aesthetically undesirable and can otherwise interfere with normal activities.